Our purposeis to investigate the effect of human interferon-beta (huIFN- β) gene cDNA engineered human bone marrow mesenchymal stem cells (hMSCs) inhibit the growth of prostate cancer cell line PC-3 (PC-3) in vitro, and investigate a therapeutic strategy about the local production of biological agents in prostate cancer by gene-manipulated hMSCs. The pCDNA3.1-IFN- β vector containing huIFN- β gene was constructed and transfected into hMSCs by lipofectamine. Effects of the hMSCs which was transfected by pCDNA3.1-IFN- β (IFN- β-hMSCs) on survival of the human prostate cancer cell line PC-3 based on in vitro Transwell experiments. PC-3 cells were trypsinized and viable cells were counted respectively at 1, 3, and 5 days using a hemocytometer after trypan blue staining. The expression of IFN- β in the medium of hMSCs-IFN- β was detected by ELISA. IFN-b-hMSCs resulted in a significant decrease in PC-3 cells survival as compared with control group [5 days after plating, the count of PC-3 cells which co-culture with IFN-b-hMSCs significantly decreased from 0.5 × 106 to (0.42±0.032) ×106, and the number of PC-3 cells in control group increased in different level]. Flow cytometry analysis showed that the IFN- β-hMSCs induced effectively the apoptosis of tumor cells (40.29%). Medium was collected and assayed using a quantitative ELISA assay for IFN- β, IFN- β-hMSCs produced 3∼4 ×103 IU of IFN- β per 105 hMSCs during the first 24 h after infection. However, there was no detectable content of IFN- β in control group. We conclude that hMSCs can integrate into prostate cancer microenviroment in vivo. The hMSCs can express IFN- β successfully after huIFN- βgene transfection and IFN- β-hMSCs cells inhibit the prostate cancer cells growth significantly as compared with control group in vitro, which may develop a new investigative strategy about gene therapy to prostate cancer.